Date: July 2022
Client: Leading independent oil & gas company
Location: UKCS
Client challenge
A global oil and gas operator commissioned our team to conduct a visual and non-invasive inspection to assess the current condition of a composite repair. The primary objective of this inspection was to identify, quantify, and document any anomalies or characteristics associated with the tested item, with the aim of evaluating its suitability for continued use.
What we did
We conducted a thorough visual and non-invasive inspection of the repair to assess its current and manufactured external condition. The non-invasive inspection employed sound waves to assess the condition of the substrate, laminate, and their inter-phase, with the goal of determining the repair’s suitability for continued use. This non-invasive examination utilised specific frequencies, and by measuring the harmonic reaction of materials, it was confirmed that anomalies exceeding 20mm in diameter could be detected within the composite, at the substrate level, and within the near surface of the parent material. As a result, this technique proved capable of pinpointing, measuring, and monitoring anomalies within the repair.
Results
The inspection uncovered two anomalies, which were attributed to the application process rather than in-service deterioration. After considering the location, depth, and appearance of these anomalies, our technical authority determined that they were associated with delaminations that occurred during the manufacturing process. Following a comprehensive technical assessment and fitness-for-service (FFS) review against acceptance criteria, it was concluded that, despite the presence of very minor dis-bonds, the identified features did not impact the integrity of the repair. This determination was based on the original defect type and the design premise used for the repair. Consequently, the written scheme of examination (WSE) was updated accordingly, and the repair has continued in service with a valid reason for extension.
